1. Technical Field
The present disclosure relates to cavity filters, and more particularly to a cavity filter with a tuning structure.
2. Description of Related Art
A cavity filter is a common feature in a mobile communication system, and comprises a housing, a cover covering on the housing, and a sliding plate. The housing comprises a positioning portion on a sidewall thereof. A plurality of resonators are fixed in the housing. The sliding plate is movably positioned on the positioning portion and between the cover and the plurality of resonators. The sliding plate comprises a plurality of adjusting units plated with a metal layer. A gap portion is defined between the sliding plate and the cover to avoid electric spark which is produced by the sliding plate touching with the cover. The sliding plate moves on the positioning portion to adjust a relative position between the plurality of adjusting units and the plurality of resonators and to adjust a resonating frequency of the cavity filter.
When the sliding plate moves to adjust the resonating frequency of the cavity filter, the sliding plate is prone to jump between the positioning portion and the cover due to the gap portion. That is, the sliding plate cannot be exactly positioned between the positioning portion and the cover. Therefore, it is difficult to accurately adjust the resonating frequency of the cavity filter.
Therefore, a need exists in the industry to overcome the described limitations.